(Adapted from Applicant's Abstract): PI M. Fabry will use blood oxygen level dependent (BOLD) magnetic resonance imaging (MRI) and other non- invasive techniques to study the impact of factors modulating vaso- occlusion on the intact animals with particular emphasis on the liver and kidneys. The investigators will examine the effect of the modulating factors nitric oxide synthase, drugs proposed for treatment of SCD (hydroxyurea, clotrimazole, and its major metabolite) and adhesion The investigators speculate that adhesion may play a major role in the liver lesions characteristic of transgenic mice.